You need to be asking all those questions to your veterinarian.

When I had a dog with mastitis, I had to give her an antiobiotic, and then, the pups needed a probiotic while she was taking the medication.

I also hot packed the affected teat with creolin 3 times a day to draw out the infection, etc.

Evenutally, a hole opened up on the side, and it drained.
All pups & mom were fine.

You'll need the antiobiotic from your vet, so better call.

M